Tunable radio frequency pulse generators

Abstract

A tunable frequency pulse generator capable of providing high energy pulses having an in-line construction includes an annularly shaped spark gap and a movable insulator support which includes a conductive sleeve that varies the resonant frequency of the generator. The input voltage is connected to the resonant element through a central aperture provided in the spark gap rings for high efficiency operation.

Having thus set forth the nature of the invention, what is claimed is: 
     
       1. A tunable radio frequency generator for providing high energy pulses comprising in combination: a. an elongated resonant cavity having an open end and an essentially closed end;   b. insulator means for varying the resonant frequency of said generator, said means adapted to movably cooperate with said cavity open end to vary the distance between said open end and said closed end and having an inwardly extending portion, said inwardly extending portion being movable along the longitudinal axis of said cavity and including support means;   c. an elongated resonant element centrally disposed within said resonant cavity, one end thereof being slidably received by the support means of said insulator means for changing its effective length, said resonant element being provided with input receiving means at its other end proximate the longitudinal axis thereof;   d. switching means disposed on said other end of said resonant element and connected to said closed end of said resonant cavity; and   e. input terminal means adapted to be coupled to a source of pulsed DC voltage and including an electrically conductive means for providing a conductive path to said resonant element input receiving means.   
     
     
       2. A tunable radio frequency generator according to claim 1 wherein said cavity open end and said insulator means are provided with cooperating threaded portions for movement of said insulator along the longitudinal axis of said resonant cavity. 
     
     
       3. A tunable radio frequency generator according to claim 1 wherein said insulator support means includes an electrically conductive sleeve for slidably engaging with said resonant element. 
     
     
       4. A tunable radio frequency generator according to claim 1 wherein said switch means comprises a spark gap formed with a pair of annular rings with a gap therebetween, one of said rings being disposed on the edge portion of said other end transverse to said longitudinal axis, the other of said rings being juxtaposed and coaxially aligned with said one ring and connected to said closed end of said resonant cavity. 
     
     
       5. A tunable radio frequency generator according to claim 4 wherein said conductive path to said resonant element input receiving means passes through a centrally disposed aperture provided in said annular spark gap rings.